talm

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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package uki
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import (
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	"debug/pe"
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	"errors"
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	"fmt"
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	"os"
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	"os/exec"
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	"path/filepath"
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)
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// assemble the UKI file out of sections.
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func (builder *Builder) assemble() error {
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	peFile, err := pe.Open(builder.SdStubPath)
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	if err != nil {
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		return err
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	}
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	defer peFile.Close() //nolint: errcheck
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	// find the first VMA address
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	lastSection := peFile.Sections[len(peFile.Sections)-1]
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	// align the VMA to 512 bytes
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	// https://github.com/saferwall/pe/blob/main/helper.go#L22-L26
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	const alignment = 0x1ff
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	header, ok := peFile.OptionalHeader.(*pe.OptionalHeader64)
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	if !ok {
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		return errors.New("failed to get optional header")
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	}
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	baseVMA := header.ImageBase + uint64(lastSection.VirtualAddress) + uint64(lastSection.VirtualSize)
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	baseVMA = (baseVMA + alignment) &^ alignment
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	// calculate sections size and VMA
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	for i := range builder.sections {
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		if !builder.sections[i].Append {
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			continue
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		}
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		st, err := os.Stat(builder.sections[i].Path)
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		if err != nil {
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			return err
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		}
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		builder.sections[i].Size = uint64(st.Size())
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		builder.sections[i].VMA = baseVMA
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		baseVMA += builder.sections[i].Size
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		baseVMA = (baseVMA + alignment) &^ alignment
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	}
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	// create the output file
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	args := []string{}
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	for _, section := range builder.sections {
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		if !section.Append {
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			continue
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		}
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		args = append(args, "--add-section", fmt.Sprintf("%s=%s", section.Name, section.Path), "--change-section-vma", fmt.Sprintf("%s=0x%x", section.Name, section.VMA))
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	}
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	builder.unsignedUKIPath = filepath.Join(builder.scratchDir, "unsigned.uki")
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	args = append(args, builder.SdStubPath, builder.unsignedUKIPath)
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	objcopy := "/usr/x86_64-alpine-linux-musl/bin/objcopy"
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	if builder.Arch == "arm64" {
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		objcopy = "/usr/aarch64-alpine-linux-musl/bin/objcopy"
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	}
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	cmd := exec.Command(objcopy, args...)
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	cmd.Stdout = os.Stdout
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	cmd.Stderr = os.Stderr
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	return cmd.Run()
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}
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